export function addClass(el, className) {
    if (hasClass(el, className)) {
        return
    }

    let newClass = el.className.split(' ');
    newClass.push(className);
    el.className = newClass.join(' ');
}

export function hasClass(el, className) {
    let reg = new RegExp('(^|\\s)' + className + '(\\s|$)');
    return reg.test(el.className);
}